WO2014040325A1

WO2014040325A1 - Edge type led backlight module, liquid crystal display device and fixation method of reflective sheet

Info

Publication number: WO2014040325A1
Application number: PCT/CN2012/082619
Authority: WO
Inventors: 胡哲彰; 曹谦
Original assignee: 深圳市华星光电技术有限公司
Priority date: 2012-09-11
Filing date: 2012-10-09
Publication date: 2014-03-20
Also published as: CN102853342B; US20140111738A1; US9007543B2; CN102853342A

Abstract

Disclosed are an edge type LED backlight module (10), a liquid crystal display device (100) and a fixation method of a reflective sheet (1). The backlight module (10) comprises a back plate (2), a side wall (6), a light guide plate (5), a light-emitting device (7), and a reflective sheet (1). The side wall (6) is connected to the back plate (2). The light guide plate (5) is disposed on the back plate (2). The light-emitting device (7) is disposed on the back plate (2). The reflective sheet (1) is disposed between the back plate (2) and the light guide plate (5). The light guide plate (5) has a light-outgoing top face (51) and a light-incoming side face (52). The light-incoming side face (52) is adjacent to the light-outgoing top face (51). The light-emitting device (7) is located between the light-incoming side face (52) and the side wall (6). The backlight module (10) further contains at least one first stretching member (13) and one second stretching member (14). Two ends of the first stretching member (13) and of the second stretching member (14) are connected to the reflective sheet (1) and the back plate (2) respectively. The backlight module (10) uses at least two stretching members (13, 14, 15, 16) to apply at least two tensile forces on the reflective sheet (1), so that the reflective sheet (1) is still in a stretched state when thermal expansion occurs to a certain extent. Hence, warping due to thermal expansion can be avoided effectively, and in turn optical properties of the backlight module (10) are improved greatly.

Description

Side-in LED backlight module, liquid crystal display device and method for fixing reflective sheet

Technical field

The invention belongs to the technical field of liquid crystal display and relates to a side-entry LED backlight module. More particularly, the present invention relates to a side-entry LED backlight module capable of preventing warpage of a reflective sheet from being heated, and a liquid crystal display device using the same, and a method of fixing a reflective sheet .

Background technique

The side-in LED backlight module has become the mainstream design of the current backlight module due to its advantages of energy saving, environmental protection, low power consumption and ultra-thin. With the maturity of LED technology, the design of backlight modules using high-power and low-number LEDs has become the trend of the times. However, with this design, the surface temperature of the LED rises rapidly, thus placing higher demands on the heat resistance of the associated optical component. In the prior art, the reflective sheet of the side-entry LED backlight module is usually close to the LED, and it is easy to expand due to the high temperature of the LED light-incident side, so that the wavy warp is generated under the heated state, affecting the entire side entry. The optical taste of the LED backlight module.

Summary of the invention

The technical problem to be solved by the present invention is to provide a method for preventing the reflection sheet from being heated when the reflection sheet is undulated by the high-temperature LED to affect the optical taste of the entire backlight module. A side-entry LED backlight module in which warpage is generated in a state to improve the optical taste of the backlight module, and a liquid crystal display device using the same, and a method of fixing a reflection sheet.

The technical problem to be solved by the present invention is achieved by the following technical solutions: a side-entry LED backlight module, comprising:

a backing plate and a side wall connected to the backboard;

a light guide plate disposed on the back plate, the light guide plate having a light-emitting top surface and a light-incident side surface adjacent to the light-emitting top surface;

a light emitting device disposed on the backplane and located between the light incident side and the sidewall;

a reflective sheet disposed between the back plate and the light guide plate,

The backlight module further includes at least a first tensile member and a second tensile member, and two ends of the first tensile member and the second tensile member are respectively connected to the reflective sheet and the back sheet.

In the above-described side-entry LED backlight module, the first tensile member and the second tensile member are symmetrically disposed with respect to a center of the reflective sheet.

In the above-described side-entry LED backlight module, the first tensile member and the second tensile member are symmetrically disposed with respect to an axis of symmetry of the reflective sheet.

In the above-mentioned side-entry LED backlight module, the backlight module further includes at least a third tensile member and a fourth tensile member, and the two ends of the third tensile member and the fourth tensile member are respectively The reflective sheet and the back sheet are connected.

In the above-mentioned side-lit LED backlight module, the back plate and the reflective sheet are both square, the side length of the back plate is larger than the side length of the reflective sheet, and the back plate and the reflective sheet are disposed in a central portion; Wherein, two ends of the first tensile member, the second tensile member, the third tensile member and the fourth tensile member are respectively connected to the four corners of the reflective sheet and the back sheet.

In the above-described side-entry LED backlight module, the first tensile member, the second tensile member, the third tensile member, and the fourth tensile member are made of an elastic material.

In the above-described side-entry LED backlight module, the first tensile member, the second tensile member, the third tensile member, and the fourth tensile member are springs or rubber bands.

In the above-described side-entry LED backlight module, the first tensile member, the second tensile member, the third tensile member, and the fourth tensile member are detachably coupled to the back sheet and the reflection sheet.

According to another aspect of the present invention, a liquid crystal display device includes a liquid crystal display panel, wherein the liquid crystal display device further includes the above-described side-entry LED backlight module.

According to another aspect of the present invention, a method of fixing a reflective sheet in a side-entry LED backlight module is provided, the method comprising: applying at least a first pulling force and a second pulling force on the reflective sheet to cause the reflecting The sheet is stretched under heat.

The present invention can obtain the following advantageous effects: in the present invention, at least two pulling forces can be applied to the reflective sheet by fixing the reflective sheet by the first tensile member and the second tensile member respectively connected to the reflective sheet and the back sheet at both ends, Under the above-mentioned pulling force, the reflective sheet can be stretched when heated and when a certain degree of thermal expansion occurs, so that the warpage caused by the thermal expansion of the reflective sheet can be effectively avoided, thereby greatly improving the backlight module. Optical taste. The liquid crystal display device of the present invention adopts the side-entry type LED backlight module having the above-mentioned anti-reflection sheet which is heated and warped, and thus has a better display effect.

DRAWINGS

The invention will be further described in detail below with reference to the drawings and specific embodiments. In the figure:

1a is a schematic diagram of a side-entry LED backlight module according to Embodiment 1 of the present invention;

Figure 1b is an enlarged schematic view of A in Figure 1a;

2a is a schematic diagram showing a relationship between a first tensile member and a second tensile member and a reflective sheet and a back sheet in a side-entry LED backlight module according to Embodiment 1 of the present invention;

2b is a schematic view showing a pulling force applied to a reflection sheet in a normal temperature state according to Embodiment 1 of the present invention;

2c is a schematic view showing a pulling force applied to a reflection sheet in a heated state according to Embodiment 1 of the present invention;

3a is a view showing a first tensile member, a second tensile member, a third tensile member, and a fourth tensile member connected to a reflective sheet and a back sheet in a side-entry LED backlight module according to Embodiment 2 of the present invention; Schematic diagram of relationship

3b is a schematic view showing a pulling force applied to a reflection sheet in a normal temperature state according to Embodiment 2 of the present invention;

Figure 3c is a schematic view showing a pulling force applied to a reflection sheet in a heated state according to Embodiment 2 of the present invention;

4 is a schematic diagram showing a relationship between a first tensile member and a second tensile member and a reflective sheet and a back sheet in a side-entry LED backlight module according to Embodiment 3 of the present invention;

Figure 5 is a schematic illustration of a liquid crystal display device in accordance with the present invention.

detailed description

The present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

The orientation of the present invention is defined as follows: in the side-entry LED backlight module (hereinafter referred to as the backlight module), the direction of light emission is forward, and the opposite direction is backward; in other words, the orientation of the liquid crystal display panel in the liquid crystal display device is The backlight module is in the rear position.

The invention provides a side-entry LED backlight module, which comprises a tensile member that applies at least two tensile forces to the reflective sheet, so that the reflective sheet can be stretched under heat and avoid existing The warpage caused by thermal expansion of the reflective sheet in the art. The details are as follows.

Example 1:

Referring to Figures 1a, 2a-2c, Figure 1a is a schematic illustration of a side-entry LED backlight module 10 in accordance with Embodiment 1 of the present invention. The backlight module 10 includes a back plate 2, a side wall 6 connected to the back plate 2, a light guide plate 5 disposed on the back plate 2, a light-emitting device 7, and a reflective sheet disposed between the back plate 2 and the light guide plate 5. 1. The light guide plate 5 of the present invention has a light-emitting top surface 51 and a light-incident side surface 52 adjacent to the light-emitting top surface 51, and the light-emitting device 7 is located between the light-incident side surface 51 and the side wall 6. The backlight module 10 further includes a first tensile member 13 and a second tensile member 14 that are connected to the reflective sheet 1 and the back sheet 2 at both ends. Specifically, the reflective sheet 1 and the back sheet 2 are both square and have a central configuration; wherein the side length of the back sheet 2 is larger than the side length of the reflective sheet 1, and the reflective sheet 1 is disposed on the back sheet 2. In Embodiment 1, the first tensile member 13 and the second tensile member 14 are both springs. As is apparent from Fig. 2a, the first tensile member 13 and the second tensile member 14 are disposed symmetrically left and right in the orientation shown in Fig. 2a (i.e., symmetrically disposed with respect to the vertical symmetry axis in the illustrated orientation), And preferably, they are respectively disposed in the middle of the left and right edges of the reflection sheet 1 and the back sheet 2.

In the connection relationship shown in Fig. 2a, the first tensile member 13 and the second tensile member 14 bring the reflection sheet 1 into a stretched state at a normal temperature. Referring to Figure 2b, F13 and F14 represent the tensile forces applied to the reflection sheet 1 by the first tensile member 13 and the second tensile member 14, respectively, and the arrows further indicate the direction of the pulling force. Preferably, both of them employ springs having the same spring constant, and apply the same magnitude of pulling force to the reflection sheet 1 at a normal temperature. In the heated state, the reflection sheet 1 expands to some extent due to the high temperature action. As shown in Fig. 2c, the broken line frame represents the size of the reflection sheet 11 at a normal temperature state, and the solid line frame next to the broken line frame represents the size (after expansion) of the reflection sheet 1 in a heated state. At this time, although the deformation of the spring is reduced due to the size of the reflection sheet 1, the spring is still in the state of tensile deformation, that is, the first tensile member 13 and the second tensile member 14 are still reflected in the heated state. The sheet 1 exerts a pulling force (F13' and F14' in Fig. 2c represent the first pulling force and the second pulling force, respectively, and the arrows indicate the directions of the first pulling force and the second pulling force). Although the pulling force applied to the reflection sheet 1 becomes small, at this time, the reflection sheet 1 is still stretched under the action of the first tensile force F13' and the second tensile force F14', thereby avoiding warpage due to thermal expansion. Also preferably, the first tensile force F13' and the second tensile force F14' are the same size and opposite directions, thereby uniformly acting on the reflective sheet 1, further improving the optical taste of the backlight module.

In Embodiment 1 of Figures 2a-2c, although the two tensile members are symmetrically disposed relative to the reflective sheet, in other embodiments, the two tensile members may also be coupled to the reflective sheet in any other manner. For example, without limitation, the two tensile members are joined to the same side of the reflective sheet, the two tensile members are joined to adjacent sides of the reflective sheet, the two tensile members are respectively coupled to the two corners of the reflective sheet, and the like. Additionally, it should be noted that the tensile members of the present invention can also be joined to the backsheet and the reflective sheet in any suitable manner. For example, but not limited to, a through hole is respectively provided in the back plate and the reflection sheet, and then the tensile member is bored in the through hole or the like. The invention is not limited to the specific connection of the above components. Preferably, however, the tensile member of the present invention is detachably coupled to the reflective sheet and the back sheet, thereby replacing the tensile member when the backlight module is used multiple times and the tensile force of the tensile member is not significant, further improving the utility of the present invention. Sex and convenience.

Example 2:

Referring to FIGS. 3a-3c, FIG. 3a is a schematic view showing the connection relationship between the first tensile member, the second tensile member, the third tensile member, and the fourth tensile member, and the reflective sheet and the back sheet according to Embodiment 2 of the present invention. The complete illustration of the backlight module is not shown here, but only the connection relationship of the above three types of components is shown. As shown in FIG. 3a, the backlight module includes a reflective sheet 1, a back sheet 2, and first and second tensile members 13 and a third stretching member respectively connected to the reflective sheet 1 and the back sheet 2, respectively. Member 15 and fourth tensile member 16. Specifically, the reflective sheet 1 and the back sheet 2 are both rectangular and co-centered; wherein the length and width of the back sheet 2 are larger than the length and width of the reflective sheet 1, and the reflective sheet 1 is disposed on the back sheet 2. In Embodiment 2, the four

tensile members

13, 14, 15, and 16 are all rubber bands. Four

tensile members

13, 14, 15 and 16 are respectively connected to the four corners of the reflection sheet 1 and the back sheet 2, the first tensile member 13 and the third tensile member 15 are centrally symmetrical, and the second tensile member 14 and The fourth tensile member 16 is centrally symmetrical.

In the backlight module of FIG. 3a, the first tensile member 13, the second tensile member 14, the third tensile member 15, and the fourth tensile member 16 bring the reflection sheet 1 into a stretched state at a normal temperature. Referring to Figure 3b, F13, F14, F15, and F16 represent the tensile forces applied to the reflection sheet 1 by the first tensile member 13, the second tensile member 14, the third tensile member 15, and the fourth tensile member 16, respectively, and the arrows further indicate the direction of the pulling force. . Since the reflection sheet 1 and the back sheet 2 are concentric, the tensile force components applied to the plane of the reflection sheet 1 by the four tensile members are all along the diagonal direction of the reflection sheet 1. Preferably, the four

tensile members

13, 14, 15, and 16 employ rubber bands having the same elastic modulus, and apply the same magnitude of tensile force to the reflection sheet 1 at a normal temperature.

In the heated state, the reflection sheet 1 will expand to some extent due to the high temperature action. As shown in Fig. 3c, the dotted line frame represents the size of the reflection sheet 1 at a normal temperature state, and the solid line frame next to the broken line frame represents the size (after expansion) of the reflection sheet 1 in a heated state. At this time, although the deformation of the rubber band is reduced due to the size of the reflection sheet 1, the rubber band is still in a state of tensile deformation, that is, the first tensile member 13 and the second tensile member 14 in a heated state. The third tensile member 15 and the fourth tensile member 16 still exert a tensile force on the reflection sheet 1 (F13', F14', F15', and F16' in Fig. 3c are applied to the four

tensile members

13, 14, 15, and 16, respectively. The first tensile force, the second tensile force, the third tensile force, and the fourth tensile force, the arrows further indicate the direction of each tensile force). Although the tensile force applied to the reflection sheet 1 becomes small, at this time, the reflection sheet 1 is still stretched under the action of four tensile forces, thereby preventing the reflection sheet 1 from being warped due to thermal expansion. Also preferably, the first tensile force F13' and the third tensile force F15' are the same size and opposite directions, and the second tensile force F14' and the fourth tensile force F16' are the same size and opposite directions, thereby uniformly acting on the reflective sheet 1, further improving the backlight mode The optical taste of the group.

Example 3:

Referring to FIG. 4, FIG. 4 is a schematic diagram showing the connection relationship between the first tensile member and the second tensile member and the reflective sheet and the back sheet according to Embodiment 3 of the present invention. This embodiment differs from Embodiment 1 only in that the positions of the two tensile members are different, and thus the complete illustration of the backlight module is omitted here. As shown in FIG. 4, the backlight module includes a first tensile member 13 and a second tensile member 14 that are respectively connected to the reflective sheet 1 and the back sheet 2 at both ends. Specifically, the reflective sheet 1 and the back sheet 2 are both square and have a central configuration; wherein the side length of the back sheet 2 is larger than the side length of the reflective sheet 1, and the reflective sheet 1 is disposed on the back sheet 2. In Embodiment 3, the first tensile member 13 and the second tensile member 14 are both springs. As is apparent from the drawing, the first tensile member 13 and the second tensile member 14 are symmetrically disposed with respect to the center of the reflection sheet 1 in the orientation shown in FIG.

In various embodiments of the present invention, the angle between each tensile member and the plane on which the reflective sheet is located (which may also be said to be the plane of the backing plate) is not more than 45°, so that its tensile force exerted on the reflective sheet The angle between the direction and the plane where the reflector is located is not more than 45°. Particularly preferably, the angle between each of the tensile members and the plane in which the reflective sheet is located is 0°, that is, the direction of action of the respective tensile forces applied to the reflective sheet is in the plane in which the reflective sheet is located. In the embodiment 1 of the present invention, as shown in Fig. 1b, the angle α between the first tensile member 13 and the plane in which the backing plate 2 is located is 19°.

In addition, the present invention also provides a liquid crystal display device 100 including a liquid crystal display panel 20 and a backlight module 10 located behind the liquid crystal display panel 20. Since the backlight module 10 having the above-described stretching member can effectively prevent the reflection sheet from warping when it is heated and expanded, it can be ensured that it provides a good illumination effect for the liquid crystal display panel 20, and finally the display effect of the liquid crystal display device 100 is improved.

In summary, in the present invention, the first tensile member and the second tensile member respectively connected to the reflective sheet and the back plate at both ends can apply at least two tensile forces to the reflective sheet, and the reflection can be performed under the tensile force. When the sheet is heated, it is still stretched when a certain degree of thermal expansion occurs, so that the warpage caused by the thermal expansion of the reflection sheet can be effectively avoided, thereby greatly improving the optical taste of the backlight module. The liquid crystal display device of the present invention adopts the side-entry type LED backlight module having the above-mentioned anti-reflection sheet which is heated and warped, and thus has a better display effect.

Claims

A side-entry LED backlight module (10) comprising:

a backboard (2) and a side wall (6) connected to the backboard (2);

a light guide plate (5) disposed on the back plate (2), the light guide plate (5) has a light-emitting top surface (51) and a light-incident side surface (52) adjacent to the light-emitting top surface (51) ;

a light emitting device (7) disposed on the back plate (2) and located between the light incident side (52) and the side wall (6);

a reflective sheet (1) disposed between the back plate (2) and the light guide plate (5),

The backlight module further includes at least a first tensile member (13) and a second tensile member (14), the first tensile member (13) and the second tensile member (14) Both ends are connected to the reflection sheet (1) and the back sheet (2), respectively.
The side-entry LED backlight module (10) according to claim 1, wherein the first tensile member (13) and the second tensile member (14) are opposite to the reflective sheet (1) The center is symmetrically set.
The side-entry LED backlight module (10) according to claim 1, wherein the first tensile member (13) and the second tensile member (14) are opposite to the reflective sheet (1) Symmetrical axisymmetric setting.
The side-entry LED backlight module (10) according to claim 1, wherein the backlight module further comprises at least a third tensile member (15) and a fourth tensile member (16), Both ends of the third tensile member (15) and the fourth tensile member (16) are respectively connected to the reflection sheet (1) and the back sheet (2).
The side-entry LED backlight module (10) according to claim 4, wherein the back plate (2) and the reflection sheet (1) are both square, and the side length of the back plate (2) is larger than The side of the reflective sheet (1) is long, and the back sheet (2) is disposed centrally with the reflective sheet (1); wherein the first tensile member (13) and the second tensile member (14) Two ends of the third tensile member (15) and the fourth tensile member (16) are respectively connected to the four corners of the reflection sheet (1) and the back sheet (2).
The side-entry LED backlight module (10) according to claim 4, wherein the first tensile member (13), the second tensile member (14), and the third tensile member (15) And the fourth tensile member (16) is made of an elastic material.
The side-entry LED backlight module (10) according to claim 4, wherein the first tensile member (13), the second tensile member (14), and the third tensile member (15) And the fourth tensile member (16) is a spring or rubber band.
The side-entry LED backlight module (10) according to claim 4, wherein the first tensile member (13), the second tensile member (14), and the third tensile member (15) And the fourth tensile member (16) is detachably coupled to the back plate (2) and the reflective sheet (1).
A liquid crystal display device (100) comprising a liquid crystal display panel (20), characterized in that the liquid crystal display device (100) further comprises the side-entry LED backlight module of any one of claims 1-8 ( 10).
A method for fixing a reflective sheet in a side-entry LED backlight module, characterized in that the method comprises: applying at least a first pulling force and a second pulling force on the reflective sheet, so that the reflective sheet is heated Is in tension.